Edge rolling tool



July 18, 1961 MILLER 2,992,470

EDGE ROLLING TOOL Filed Feb. 16, 1959 INVENTOR RAYMOND A. MILLER ATTORNEYS,

United States Patent 2,992,470 EDGE ROLLING TOOL Raymond A. Miller, 1101 Orchard Drive, Louisville 13, Ky. Filed Feb. 16, 1959, Ser. No. 793,647 1 Claim. (CI. 29-11) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to a tool for rolling the edges of the grooves of the rifling in a gun barrel.

. Heretofore it was the practice to produce the desired radius on the corners of the rifling groove lands by a series of chamfering operations with broaching cutters. These operations consisted, generally, of a chamfering cut at a 45 angle and two more cuts at 22% to attempt to produce a radius. It was almost impossible to get unitormity in all of the edges of the grooves. The accuracy depended on the accuracy of the cutters and the spiralling mechanism of the riflin-g machine. The degree of accuracy desired was almost impossible to produce and even when accurate was still not the true radius which was the goal. Experiments were then carried out with rollers which could be mounted on the end of a rifling head and caused to bear on the edges of the grooves or the corners of the lands of the rifling.

An object of the present invention is to produce, by rolling, a true radius on the edges of the rifling grooves of a gun barrel.

Another object of the present invention is to provide a pair of rollers, approximately 180 apart, affixed to a holder so that they can be brought to bear on the edges of substantially opposite n'fiing grooves of a gun barrel.

Still another object of the invention is to provide rollers which engage each other at their circumference diametrically opposite to the engagement with the edges of the grooves to provide the necessary outward force to roll the edges.

It is still another object of the invention to provide rollers, either single rollers, double rollers or a plurality of rollers, which may be utilized by a single traverse of the gun barrel to produce the desired radius of curvature on one or more of the edges of the r-ifling grooves.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of the assembly;

FIG. 2 is a section on line 2-2 of FIG. 1;

FIG. 3 is an enlarged plan view of the rollers as mounted in the holder;

FIG. 4 is a perspective view of a modified form showing three rollers mounted in the holder;

FIG. 5 is an enlarged view of a portion of one of the rollers, used in pairs, showing the engagement with the edges of the rifiing groove.

Referring particularly to FIG. 1 a gun 8, rifled as shown at is fitted with the rolling tool carried on an adapter which is attached to a rifling head 12. The rolling tool is composed of a holder 14 having journaled therein a pair of rollers 16 and 18. The rollers are mounted on shafts 20 and 22 respectively which are carried in bores 24 and 26 in the holder. Set screws 28 hold the shafts in position in the bores. The bores 24 and 26 are at an angle of 536'25 with a plane perpendicular to the longitudinal axis of the holder making ice 2 the rollers at the same angle of 53 6'25 to the longitudinal axis of the holder. This angle is necessary and is the same as the helix angle of the riding groove of a 3 inch 50 caliber gun, the type with which the invention is illustrated. For guns of different size and helix angle this angle would be different. The rollers 16 and 18 journaled on the staffs are mounted in accurately machine slots 30 and 32 respectively, the side walls of which serve as guides for the rollers. These rollers are mounted diametrically opposite and are ground to a slightly convex diameter which enables mounting of the two rollers with their circumferences in contact at their center line, with the sum of the roller diameters less than the groove diameter to provide clearance between the rollers and the bottom of the grooves. It is believed that this contact of the rollers provides a constant rolling pressure Without causing strain on the roller mounting The radius desired at the edges of the rifling grooves, before plating, is usually .015 to .016" and is ground peripherally on the two edges of the rollers with the centers of the radii located diametrically and laterally spaced as required to develop the desired radii (FIG. 5). The horizontal and vertical tangents to these radii are angularly relieved to prevent the development of shoulders and provide for blending of the radii with the bore of the barrel and the sides of the grooves. With this arrangement both edges of any two diametrically opposite rifling grooves can be rolled by pushing the rolling tool through the barrel.

The radii are generally rolled on the edges of the riiling grooves after the grooves have been cut to depth and width and chamfered slightly at 45 (this charnfering operation may be eliminated), by placing the holder on an adapter 36 and then fitting the adapter to the rifling head. The tool is then turned until the rollers line up with a pair of grooves in the barrel and pushed entirely through the barrel, the holder being slipped off the adapter at the breech end of the barrel and the rifling head and adapter withdrawn. The operation is repeated with the next pair of grooves until the job is completed, making half as many passes as the number of rifting grooves.

By rolling the edges of the grooves the radii 38 can be controlled accurately and consistently. This is possible as each groove is rolled individually according to the characteristics of the particular machined groove with no dependency upon the accuracies of the other grooves, the diameter of the bore or the spacing accuracies of the tool itself. Radii are always equal as the rollers align themselves from the edges of the grooves and due to even distribution of pressures roll the radii evenly. The rolling procedure will also produce a finer grain structure at the edges of the grooves and will improve both the physical properties and the plating.

Referring to FIG. 4 a modification is shown in which a holder 40 having rollers 42, 4.4 and 46 each journaled on its shaft similar to rollers 16 and 18. Where the number of riding grooves is divisible by three, such a tool as shown in FIG. 4 can be used to advantage. Other tools having a single roller to any desired multiple may be utilized, employing the principles set forth in the two and three roll tool.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

A tool for rolling a curved surface on each edge of two selected diametrically opposed grooves in a gun Patented July 18, 1961 barrel comprising: a generally cylindrical holder adapted to be secured to an elongated bar, said bar being used to transmit the force needed to drive said holder through said gun barrel, said holder having a size which will clear theseveral lands in said barrel when said bar moves said holder through said barrel, said holder having a centrally disposed bore formed in its leading end and having .two opposed straight sided slots each extending from said =bore to the outside of said holder, said slots beingcanted generally as the rifling in said barrel in the direction from said leading end to the respective trailing end of each slot; two substantially identical rollers each of substantially uniform thickness and with flat sides thereon, each roller being mounted for rotation in a respective one of said slots, said rollers tangentially contacting each other along the axis of said bore at all stages of said rotation, each of said rollers having a cylindrical portion bounded at each end thereof by a respective one of two re-entrant toroidal surfaces which are essentially the mirror image one of the other, said cylindrical portion being narrower than each groove in said barrel, the edge of eaoh of said toroidal surfaces that ends at the adjacent respective one of said flat sides being a circle of substantially smaller diameter than the 4 7 diameter of said cylindrical portion, two times the diameter of said cylindrical portion being substantial greater than the diametrical distance between opposed lands in said barrel; whereby said rollers are started in the said two selected grooves and, due to the cant of said slots, said rollers will roll in helical paths corresponding to the lay of said two selected grooves when said tool is moved within said barrel; and whereby said toroidal surfaces will round the edges on said two selected grooves as said tool -is moved bodily "along and within said barrel.

References Cited in the file of this patent UNITED STATES PATENTS 401,331 Orossley 'Apr. 16, 1889 425,807 Leach Apr. 15, 1890 1,884,467 Windsor Oct. 25, 1932 2,127,809 Cuppers Aug. 23, 1938 2,276,007 Young Mar. 10, 1942 2,810,185 Simons Oct. 22, 1957 FOREIGN PATENTS 14,290 Great Britain Nov. 21, 1,885 78,565 Switzerl nd Ian. 2, 1919 

